2,097 research outputs found
Paredes de tapial y su industrialización (encofrados y sistemas de compactación)
Rammed earth is a material that is characterized by its thermal inertia and excellent hygrothermal behavior, which together with the added value of sustainability and the tectonic strength of its mass, make it an interesting element to incorporate in architectural projects.
In general, rammed earth as a construction technique needs an intense amount of work and ability. In this sense, the industrialization in the production of rammed walls would rationalize the costs of labor and execution times, as well as provide improvements in areas such as earth and water metering, control of quality of execution, in particular the degree of compaction and, of course, the final finish. Prefabrication allows the integration of electrical and air conditioning installations, increasing the qualities of the earth.
Prefabrication is a step towards the modernization of earth construction, which has inherent a strong added value of sustainability on which we try to open new ways to facilitate its use in building and as a part of the architectural design.El tapial como material se caracteriza por su inercia térmica y por un excelente comportamiento higrotérmico, que unidos al valor añadido inherente de la sostenibilidad y la fuerza tectónica de los muros, convierten a este material en un elemento de interés a incorporar en los proyectos de arquitectura actuales.
En general, el tapial como técnica de construcción con tierra necesita una intensiva cantidad y capacidad de trabajo. En este sentido la industrialización en la producción del tapial permitiría una racionalización de los costes de la mano de obra y tiempos de ejecución, a los que se podrían añadir mejoras en aspectos como la dosificación de tierra y agua, el control de calidad de ejecución, en especial el grado de compactación y, por supuesto, del acabado final.
La prefabricación con tierra permite una ejecución flexible en dimensiones e incluso integrar instalaciones eléctricas y de climatización, para no afectar al aspecto final de la superficie del muro de tierra.
La prefabricación es un paso más hacia la modernización de la construcción con tierra, y ha de abrir camino a un material como la tierra cruda en el mercado de la edificación y, en el fondo, ayudando a encontrar alternativas que nos aproximen a la sostenibilidad
Spectral modeling of gaseous metal disks around DAZ white dwarfs
We report on our attempt for the first non-LTE modeling of gaseous metal
disks around single DAZ white dwarfs recently discovered by Gaensicke et al.
and thought to originate from a disrupted asteroid. We assume a Keplerian
rotating viscous disk ring composed of calcium and hydrogen and compute the
detailed vertical structure and emergent spectrum. We find that the observed
infrared CaII emission triplet can be modeled with a hydrogen-deficient gas
ring located at R=1.2 R_sun, inside of the tidal disruption radius, with Teff
about 6000 K and a low surface mass density of about 0.3 g/cm**2. A disk having
this density and reaching from the central white dwarf out to R=1.2 R_sun would
have a total mass of 7 10**21 g, corresponding to an asteroid with about 160 km
diameter.Comment: Proceedings, 16th European White Dwarf Workshop, Barcelona, 200
Transverse and longitudinal correlation functions in the Intergalactic Medium from 32 close pairs of high-redshift quasars
We present the transverse flux correlation function of the Lyman-alpha forest
in quasar absorption spectra at z~2.1 from VLT-FORS and VLT-UVES observations
of a total of 32 pairs of quasars; 26 pairs with separations in the range
0.6<theta<4 arcmin and 6 pairs with 4<theta<10 arcmin. Correlation is detected
at the 3sigma level up to separations of the order of ~4 arcmin (or ~4.4 h^{-1}
Mpc comoving at z=2.1 for Omega_{m}=0.3 and Omega_{Lambda}=0.7). We have,
furthermore, measured the longitudinal correlation function at a somewhat
higher mean redshift (z=2.39) from 20 lines of sight observed with high
spectral resolution and high signal-to-noise ratio with VLT-UVES. We compare
the observed transverse and longitudinal correlation functions to that obtained
from numerical simulations and illustrate the effect of spectral resolution,
thermal broadening and peculiar motions. The shape and correlation length of
the correlation functions are in good agreement with those expected from
absorption by the filamentary and sheet-like structures in the photoionized
warm intergalactic medium predicted in CDM-like models for structures
formation. Using a sample of 139 C_{iv} systems detected along the lines of
sight toward the pairs of quasars we also investigate the transverse
correlation of metals on the same scales. The observed transverse correlation
function of intervening C_{iv} absorption systems is consistent with that of a
randomly distributed population of absorbers. This is likely due to the small
number of pairs with separation less than 2 arcmin. We detect, however, a
significant overdensity of systems in the sightlines towards the quartet
Q0103-294A&B, Q0102-2931 and Q0102-293 which extends over the redshift range
1.5<z<2.2 and an angular scale larger than 10 arcmin.Comment: accepted for publication in MNRAS, Appendix B and C will be published
online onl
Ultra-heavy cosmic-ray science--Are r-process nuclei in the cosmic rays produced in supernovae or binary neutron star mergers?
The recent detection of 60Fe in the cosmic rays provides conclusive evidence
that there is a recently synthesized component (few MY) in the GCRs (Binns et
al. 2016). In addition, these nuclei must have been synthesized and accelerated
in supernovae near the solar system, probably in the Sco-Cen OB association
subgroups, which are about 100 pc distant from the Sun. Recent theoretical work
on the production of r-process nuclei appears to indicate that it is difficult
for SNe to produce the solar system abundances relative to iron of r-process
elements with high atomic number (Z), including the actinides (Th, U, Np, Pu,
and Cm). Instead, it is believed by many that the heaviest r-process nuclei, or
perhaps even all r-process nuclei, are produced in binary neutron star mergers.
Since we now know that there is at least a component of the GCRs that has been
recently synthesized and accelerated, models of r-process production by SNe and
BNSM can be tested by measuring the relative abundances of these ultra-heavy
r-process nuclei, and especially the actinides, since they are radioactive and
provide clocks that give the time interval from nucleosynthesis to detection at
Earth. Since BNSM are believed to be much less frequent in our galaxy than SNe
(roughly 1000 times less frequent, the ratios of the actinides, each with their
own half-life, will enable a clear determination of whether the heaviest
r-process nuclei are synthesized in SNe or in BNSM. In addition, the r-process
nuclei for the charge range from 34 to 82 can be used to constrain models of
r-process production in BNSM and SNe. Thus, GCRs become a multi-messenger
component in the study of BNSM and SNe.Comment: Astro2020 Science White Pape
Mapping interactions with the chaperone network reveals factors that protect against tau aggregation.
A network of molecular chaperones is known to bind proteins ('clients') and balance their folding, function and turnover. However, it is often unclear which chaperones are critical for selective recognition of individual clients. It is also not clear why these key chaperones might fail in protein-aggregation diseases. Here, we utilized human microtubule-associated protein tau (MAPT or tau) as a model client to survey interactions between ~30 purified chaperones and ~20 disease-associated tau variants (~600 combinations). From this large-scale analysis, we identified human DnaJA2 as an unexpected, but potent, inhibitor of tau aggregation. DnaJA2 levels were correlated with tau pathology in human brains, supporting the idea that it is an important regulator of tau homeostasis. Of note, we found that some disease-associated tau variants were relatively immune to interactions with chaperones, suggesting a model in which avoiding physical recognition by chaperone networks may contribute to disease
Combination of bevacizumab and 2-weekly pegylated liposomal doxorubicin as first-line therapy for locally recurrent or metastatic breast cancer. A multicenter, single-arm phase II trial (SAKK 24/06)
Background: Pegylated liposomal doxorubicin (PLD) and bevacizumab are active agents in the treatment of metastatic breast cancer (MBC). We carried out a multicenter, single-arm phase II trial to evaluate the toxicity and efficacy of PLD and bevacizumab as first-line treatment in MBC patients. Methods: Bevacizumab (10 mg/kg) and PLD (20 mg/m2) were infused on days 1 and 15 of a 4-week cycle for a maximum of six cycles. Thereafter, bevacizumab monotherapy was continued at the same dose until progression or toxicity. The primary objective was safety and tolerability, and the secondary objective was to evaluate efficacy of the combination. Results: Thirty-nine of 43 patients were assessable for the primary end point. Eighteen of 39 patients (46%, 95% confidence interval 30% to 63%) had a grade 3 toxicity. Sixteen (41%) had grade 3 palmar-plantar erythrodysesthesia, one had grade 3 mucositis, and one severe cardiotoxicity. Secondary end point of overall response rate among 43 assessable patients was 21%. Conclusions: In this nonrandomized single-arm trial, the combination of bimonthly PLD and bevacizumab in locally recurrent and MBC patients demonstrated higher than anticipated toxicity while exhibiting only modest activity. Based on these results, we would not consider this combination for further investigation in this settin
Adding cetuximab to capecitabine plus oxaliplatin (XELOX) in first-line treatment of metastatic colorectal cancer: a randomized phase II trial of the Swiss Group for Clinical Cancer Research SAKK
Background: To determine the activity and tolerability of adding cetuximab to the oxaliplatin and capecitabine (XELOX) combination in first-line treatment of metastatic colorectal cancer (MCC). Patients and methods: In a multicenter two-arm phase II trial, patients were randomized to receive oxaliplatin 130 mg/m2 on day 1 and capecitabine 1000 mg/m2 twice daily on days 1-14 every 3 weeks alone or in combination with standard dose cetuximab. Treatment was limited to a maximum of six cycles. Results: Seventy-four patients with good performance status entered the trial. Objective partial response rates after external review and radiological confirmation were 14% and 41% in the XELOX and in the XELOX + Cetuximab arm, respectively. Stable disease has been observed in 62% and 35% of the patients, with 76% disease control in both arms. Cetuximab led to skin rash in 65% of the patients. The median overall survival was 16.5 months for arm A and 20.5 months for arm B. The median time to progression was 5.8 months for arm A and 7.2 months for arm B. Conclusion: Differences in response rates between the treatment arms indicate that cetuximab may improve outcome with XELOX. The correct place of the cetuximab, oxaliplatin and fluoropyrimidine combinations in first-line treatment of MCC has to be assessed in phase III trial
Direct Dynamic Protein-Affinity Selection Mass-Spectrometry
A new methodology is described enabling the affinity screening of potential ligands towards the human estrogen receptor alpha ligand binding domain (ERα-LBD). In-solution incubation is performed of the analyte and the His-tagged ERα-LBD. The bound complex is immobilized on a nickel-loaded protein-affinity selection column, where after the unbound fraction is removed. The immobilized protein–ligand complex is exposed to a decreased pH value and an increased organic modifier concentration releasing the ligand for MS detection, and precipitating the proteins on a filter positioned between the affinity column and the mass spectrometer. The trapping column can be regenerated for reuse at least 70 times. The advantages of the methodology over existing methodologies are the absence of a pre-concentration as well as a chromatographic separation step, resulting in a significantly shorter analysis time compared to previously described procedures, and in addition, allowing the determination of solutes with unfavorable chromatographic properties. The overall analysis time now can be reduced about 250% to approximately 6 min. Replacing the filters after every measurement results in an intra-day standard deviation of 14.8% and an inter-day standard deviation of 21.3%
Ambiguous Nucleotide Calls From Population-based Sequencing of HIV-1 are a Marker for Viral Diversity and the Age of Infection
The fraction of ambiguous nucleotide calls in bulk sequencing of human immunodeficiency virus type 1 (HIV-1) carries important information on viral diversity and the age of infection. In particular, a fraction of ambiguous nucleotides of >.5% provides evidence against a recent infection event <1 year ago
Sensitivity and specificity of the Hyperdense Artery Sign for arterial obstruction in acute ischemic stroke
BACKGROUND AND PURPOSE: In acute ischemic stroke, the Hyperdense Artery Sign (HAS) on non-contrast CT is thought to represent intra-luminal thrombus and therefore is a surrogate of arterial obstruction. We sought to assess the accuracy of HAS as a marker of arterial obstruction by thrombus. METHODS: The Third International Stroke Trial (IST-3) was a randomized controlled trial testing use of intravenous thrombolysis for acute ischemic stroke in patients who did not clearly meet the prevailing license criteria. Some participating IST-3 centers routinely performed CT or MR angiography (CTA and MRA, respectively) at baseline. One reader assessed all relevant scans independently, blinded to all other data; we checked observer reliability. We combined IST-3 data with a systematic review and meta-analysis of all studies that assessed the accuracy of HAS using angiography (any modality). RESULTS: IST-3 had 273 patients with baseline CTA or MRA and was the largest study of HAS accuracy. The meta-analysis (n=902+273=1175, including IST-3) found sensitivity and specificity of HAS for arterial obstruction on angiography to be 52% and 95%, respectively. HAS was more commonly identified in proximal than distal arteries (47% versus 37%, p=0.015), and its sensitivity increased with thinner CT slices (r=−0.73, p=0.001). Neither extent of obstruction nor time after stroke influenced HAS accuracy. CONCLUSIONS: When present in acute ischemic stroke, HAS indicates a high likelihood of arterial obstruction, but its absence indicates only a 50/50 chance of normal arterial patency. Thin-slice CT improves sensitivity of HAS detection
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